The study took a dozen people and kept them up all night. With the help of an MRI scanner, participants' brain responses to images of food were examined.

The results? The study showed that sleep-deprived people sought food in a more focused manner and anticipated their next meal more strongly than those who had been well rested.

A small segment of the brain known as the Anterior Cingulate Cortex (ACC) lit up more brightly than a normal person’s ACC. Those with the biggest changes in brain activity in the ACC also reported the biggest appetite.

Although a single night of sleep deprivation is not exactly comparable to the chronic sleep deprivation that shift workers tend to suffer from, supporting evidence also comes from other studies looking at other appetite hormone signals like ghrelin and leptin. These studies suggest that the effects of sleep deprivation, even chronic sleep deprivation, are similar - too little sleep = greater appetite relative to energy needs.

This leaves us with a riddle. If you have to get up an hour early to fit your workout in, do the benefits of the exercise outweigh the downside of sleep deprivation?

To my mind, exercise has so many benefits that it’s still worthwhile. The ideal way is to organize your life so that you can sleep enough and still get exercise.